Lock system

ABSTRACT

A lock arrangement comprising a cylinder lock with turnable locking disks and a number of different keys. One or several of the keys are normal keys for normal operation of the lock, but there are also a first special key by means of which a locking of the normal function of the lock can be obtained, and a second special key which is used to release this locking. The first special key is provided with means for turning a number of the locking disks into one turning direction and for bringing a smaller number of the locking disks back into their initial position, thereby leaving the return of at least one locking disk incomplete. The incompletely returned locking disk forms an obstacle in the keyway of the lock and prevents proper insertion of the normal key.

[ Nov. 13, 1973 LOCK SYSTEM Primary Examiner-Albert G. Craig Jr.Inventor: Paul Kriikstriim, Helsinki, Finland Attmey waters RodmSchwartz & Nlssen Assignee: 0y Wartslla Ab, Helsinki, Finland ABSTRACT1971 i A lock arrangement comprising a cylinder lock with Appl. No.:135,171 turnable locking disks and a number of different keys. One orseveral of the keys are normal keys for normal 70/338, 7O/366, 7O/407operation of the lock, but there are also a first special 70/4O9 key bymeans of whlch a locking of the normal func- Int. EOSb /02, EOSb /08 canbe Obtametd' a specal key WlllCh is used to release this locking. Thefirst spe- Fleld of Search...................... /338, 339, 366, 1k d fb 70/4O7 409 cm ey 1S provr e Wlt means or turning a num er of thelocking disks mto one turning direction and for bringing a smallernumber of the locking disks back References Cited Into their initialposition, thereby leaving the return of UNITED STATES PATENTS at leastone locking disk incomplete. The incompletely Unite States atentKrikstriim [22] Filed:

8 Claims, 4 Drawing Figures returned locking disk forms an obstacle inthe keyway of the lock and prevents proper insertion of the normal key.

m m m Koskinen et um am. co ab BFC 500 1917 9899 llll l 4l 0279 6 781431 6252 ll 3 LOCK SYSTEM The invention relates to a lock and keysystem to which belongs a cylinder lock comprising a stationary cylinderhousing enclosing a rotatable lock cylinder in which there are aplurality of locking disks turnable by means of the key of the lock,which disks by turning of the key in one direction are brought into acylinder releasing position and by reverse turning of the key are by areturn surface on the key brought back to their initial position.

In the Finnish patent application No. 1640/69, which is still pending, alock is disclosed which can be temporarily locked so that it cannot beopened with its normal key. However, this lock has the drawback that ithas to be provided with a special locking disk, whereby the lock becomesmore expensive than a standard lock. The use of the lock is alsorelatively complicated.

The object of the invention is to provide a cylinder lock with turnablelocking disks which can be temporarily locked so that the normal key ofthe lock does not work, but which at the same time is as simple aspossible and deviates from a standard lock as little as possible. Theinvention is characterized in that the lock system comprises a specialkey with a return surface provided with such a recess that the returnmovement of preferably one of the innermost locking disks of the lockremains incomplete. Due to this incomplete return, the normal key cannotbe pushed into its proper position, i.e., to the bottom of the lock, andhence, the use of the normal key is prevented. In order to obtain thiskind of locking, a special key is needed, and in order to remove thelocking another special key is needed. However, the lock itself does nothave to be changed in any way, it is still a normal standard lock.

In a preferred embodiment of the invention, there is in front of thelocking disk which is to be incompletely returned a so called fixedlocking disk, the turning of which relative to the lock cylinder isprevented. If this fixed locking disk would not be situated'in front ofthe incompletely returned locking disk, it would be possible to turnback the incompletely returned locking disk to its initial position witha normal key even if this operation would be relatively complicated toperform. The fixed locking disk gives the advantage that the releasingofthe locking is quite impossible to perform with a normal key.

The recess in the return surface of the special key usually has the formof a circular sector. The extent of the sector removed determines thedegree of incom sition of the fixed locking disk, but this makes the keyvery weak. As the key in question is a special key, the object of whichmerely is to provide a locking of the lock, the strength of the key canbe improved by making the cut at the position of the fixed locking disksmaller than a right angle.

To release the locking of the lock a second special key is needed beingprovided at its end on the side of the return surface with a helical oroblique surface by means of which the incomplete return of the lockingdisk can be made complete by pushing the key in an axial direction intothe lock. In order to secure that this reset key functions in theintended way, said helical or oblique surface is preferably arranged sothat it extends through a key sector which is somewhat larger than theangle corresponding to the incomplete return of the locking disk. Saidhelical or oblique surface can also be made in a normal key of the lockor in any other special key which may belong to the locking system. Themaking of the helical or oblique surface will in general be somewhateasier if there is a groove or a groove-like recess at the position oftheturning' axis of the key in question.

In the following, the invention will be more fully described withreference to the attached drawing in which FIG. 1 shows an axial sectionthrough a lock according to the invention, 7

FIG. 2 shows a cross-section of a key belonging to this lock,

FIG. 3 shows a special key needed to obtain locking of the normalfunction of the lock, and

FIG. 4 shows a special key needed to release said locking.

In the drawing, 10 indicates the stationary cylinder housing of acylinder lock, 11 a lock cylinder rotatable in the cylinder housing, 12locking disks, and 13 a so called fixed locking disk. The lock isoperated by keys having a basicly semicylindrical blade portion. FIG. 2shows schematically a cross-section of this kind of a key.

From the one half of the key, sectors of different extent are removed bymeans of milling, and the extent of the sector removed determines howmuch the key is able to turn the locking disks 12 of the lock. Thedifferent cuts are in FIG. 2 indicated by numerals 0,1,2,3,4, and 5,whereby 5 indicates the greatest cut and 0 the smallest, i.e., thatnothing has been cut from the key. A zero cut turns the locking diskthrough the greatest angle and a five-cut does not turn the locking diskat all. Consequently, there has to be a five-cut in the key at theposition of the fixed locking disk 13. The other half of the key, thatis thesurface 14, works as a return surface and returns the lockingdisks 12 to their initial position during the return movement of thekey.

In the return surface 14 of the special key shown in FIG. 3, there is atthe end of the key a recess 15 having the form of a three-cut of anormal key. If the lock is provided with a fixed locking disk 13, thekey has to be provided with a cut in the opposite side of the key at theposition of this locking disk. This cut does not have to be a five-cut,because, the locking of the normal function of the lock does not requireas great a turning of the key as the normal use of the lock.Consequently, the cut 16 at the position of the fixed locking disk canalso be a three-cut. By this means the advantage is obtained that theportion of the key where the cuts 15 and 16 meet will not be too weak.

In FIG. 4, a second special key is shown the object of which is torelease the locking obtained by use of the key shown in FIG. 3. At theend of the return surface 14 of this second special key, there is ahelical or oblique surface 17 covering a key sector, which seen in anaxial direction of the key is somewhat larger than the cut 15, so thatthe desired returning of the locking disk with certainty will beobtained when the key is axially pushed into the lock. The making of thehelical or oblique surface 17 is somewhat easier if a groove-like recess18 is made in the plane surface of the key.

I claim:

1. A lock arrangement comprising a cylinder lock and a number ofdifferent keys, said cylinder lock comprising a stationary cylinderhousing and a cylinder rotatable therein, said cylinder enclosing aplurality of locking disks turnable by at least one of said keys wheninserted into said lock, said last mentioned key being a normal key usedfor normal operation of said lock, another of said keys being a firstspecial key provided with means for turning a number of said lockingdisks into one turning direction and for bringing a smaller number ofsaid locking disks back into their initial position, thus leaving thereturn of at least one locking disk incomplete so as to form an obstaclein the keyway of the lock preventing proper insertion of said normalkey.

2. An arrangement according to claim 1, in which said means for leavingthe return of one locking disk incomplete consists of a recess made inone side of said first special key.

3. An arrangement according to claim 1, in which said lock is providedwith a locking disk being fixed against turning relative to saidcylinder and situated in front of said locking disk which is to beincompletely returned.

4. An arrangement according to claim 2, in which,

said recess is included in a sector having its apex on the turning axisof said first special key and an apex angle of at the most 60.

5. An arrangement according to claim 3, in which said first special keyis provided at a position corresponding to the position of said fixedlocking disk with a cut included in a sector having its apex on theturning axis of said first special key and having an apex angle ofconsiderably less than 6. An arrangement according to claim 1,comprising a second special key having at its end on one side of agenerally oblique surface engaging said incompletely returned lockingdisk when said second special key is axially pushed into said lock.

7. An arrangement according to claim 6, in which said generally obliquesurface extends through a sector having its apex on the turning axis ofsaid second special key and being somewhat larger than the angle ofincompleteness of the incompletely returned locking disk.

8. An arrangement according to claim 6, in which said second special keyis at its end, adjacent toysaid generally oblique surface provided witha central groove.

1. A lock arrangement comprising a cylinder lock and a number ofdifferent keys, said cylinder lock comprising a stationary cylinderhousing and a cylinder rotatable therein, said cylinder enclosing aplurality of locking disks turnable by at least one of said keys wheninserted into said lock, said last mentioned key being a normal key usedfor normal operation of said lock, another of said keys being a firstspecial key provided with means for turning a number of said lockingdisks into one turning direction and for bringing a smaller number ofsaid locking disks back into their initial position, thus leaving thereturn of at least one locking disk incomplete so as to form an obstaclein the keyway of the lock preventing proper insertion of said normalkey.
 2. An arrangement according to claim 1, in which said means forleaving the return of one locking disk incomplete consists of a recessmade in one side of said first special key.
 3. An arrangement accordingto claim 1, in which said lock is provided with a locking disk beingfixed against turning relative to said cylinder and situated in front ofsaid locking disk which is to be incompletely returned.
 4. Anarrangement according to claim 2, in which said recess is included in asector having its apex on the turning axis of said first special key andan apex angle of at the most 60*.
 5. An arrangement according to claim3, in which said first special key is provided at a positioncorresponding to the position of said fixed locking disk with a cutincluded in a sector having its apex on the turning axis of said firstspecial key and having an apex angle of considerably less than 90*. 6.An arrangement according to claim 1, comprising a second special keyhaving at its end on one side of a generally oblique surface engagingsaid incompletely returned locking disk when said second special key isaxially pushed into said lock.
 7. An arrangement according to claim 6,in which said generally oblique surface extends through a sector havingits apex on the turning axis of said second special key and beingsomewhat larger than the angle of incompleteness of the incompletelyreturned locking disk.
 8. An arrangement according to claim 6, in whichsaid second special key is at its end, adjacent to said generallyoblique surface provided with a central groove.